| 摘要 |
A system to control fluid flow through a fluid passage includes a valve that is fail-safe closed to selectively control fluid flow through the fluid passage, and a hydraulic actuator operatively coupled to the valve to open the valve when hydraulic pressure above a predetermined amount is received. The system further includes an inlet to provide hydraulic pressure to the hydraulic actuator and open the valve and an outlet to vent hydraulic pressure from the hydraulic actuator and close the valve. |
